Aeroplane-propeller



S. D. MOTT.

AEROPLANE PROPELLER.

' APPLICATION FILED APR. l. l9l6. 4 1,361,399 Patented Dec. 7, 1920.

a SHEETS-SHEET l.

W fm

S. D. MOTT. AEROPLANE PRoPELLER.

Patented D60. 7,1920.

'APPLICATION FILED APR. I I9I6.

3 SHEETS-SHEET 2.

. Q WITNESSEE r s. D. MOU. AEROPLANE PROPELLER.

APPLICATION FILED APR- l. 1916.

. 1,361,399 Patented Dec. 7,1920.

` a sH EEEEEE HET '3.

www;

SAMUEL D. MOTT, OF

rAssAIc, NEW .1EEsEY,-Ass1GNoE 0E ONE-HALF To ARTHUR B.

SULLIVAN. or; ALLENIMuse,` NEW JERSEY.

AEROPLANE-PROPELLER.

Application filed April 1,

To all whom t may concern.

Be it known that I, SAMUEL D. Morr, a citizen of the United States, resident of and whose post-office address is '130 Autumn street, in the city of Passaic, county of Passaic, and State of New Jersey, -have invented certain new and useful Improvements in Aeroplane-Propellers, of which the following is a description, reference being had to the drawings forming a part hereof.

This invention relates to prop'ellers and more particularly the construction of such peculiarly adapted to meet the conditions of air propellers lon aircraft of any sort. The increase of power used for'propulsion of aircraft, has been rapid and has necessitated the use of increased sizes of. propellers and to absorb the power now used or contemplated in aeroplanes or dirigibles, the limit of strength of the simple propeller blade is being rapidly reached. To secure' necessary strength vwith a blade supported solely by a central hub, the size of hub and butt of the blade increase to a point where the central solid mass presentsa substantial resistance.

My construction isintended to meet the new conditions and afford a` stronger construction with less central or hub resistance, and to prevent or minimize the `deflection of the blade due to the strain incident to the absorption of great power, whilelaffording a lighter construction to meet the operative conditions, also facilitating the manufacture and assembly.

A particular forni of construction hereinafter described, is shown in the accompanying` drawings, in which:

Figure 1 is the central portion of a threeblade propeller, the outer portions being broken away.

Fig` 2 is a developed section on the line a#2 of Fig. 1.

Fig. 3 is va section on the plane in the axis of the propeller.

Fig.v l'is a side view of a broken nportion of the blade showing'rnodifiediarrangernent of brace connections. N

Fig.' `5 is an enlarged section of. abrace ma 1 Fig. 6 is a side elevation of half 'ofja three-'rim-brace or trusshub.

VFig. 7 is a diagrammatic section atl'Z-' 4of Figli.

1n the drawings, A@ are blades, B isy amb,

Specification of Letters Patent.

Patented Dec. 7, 1920. 1916. serial No. 88,193. i l

C a shaft, D--D are circular braces constituting the rims of skeleton hubs, E is a central'brace or rim of a central skeletonhub,

F-F are sockets to clamp the circular braces tothe propeller. These sockets, as shown in Fig. 2, may involve split ferrules f-f beveled at one end to the Obliquity of the blade surface, withnuts f on suitably threaded portions, notV shown, of the circular braces,'or the ends of the ferrules f-f may be splitand the ends taper-threaded on the outside soV that the nuts f will clamp them tight to the ycircular braces D and E, with any other suitable locating pins or studs or roughened surface, et cetera, to assist in strengthening and locking'of the sockets into place. i l

The circular braces D and E constitute respectivelv, each therim of aiwire wheel or truss tension wheel structure, and for convenience ini'further reference these respective wheels may be referred to as D and'E,

or D when the entire wheel structure is meant, and not only the circular brace.

These tension wheels D comprise the hub portions Gand the spokes el and d, and in Fig. 3 the spokes Z run from the hubf collar G to the rim D, and are suitably fastened,as indicated in'Fig. 5, by means of nipple and nuts, or are secured in any other suitable manner; while spokes al run'fvrom the rim tothe shaft C, thereby carrying lthe strain direct to the central shaft member. `The spokes e-c run from the circular brace'E, constituting the rim, toy the lflanges of the central hub B, while additionalspokes e maybe used running directly from the rim normal or directly radial to the central'shaft C. In this Fig. 3, the center or butt end of the propeller a is shown as formin a small hub held in place betweenanges o the hub B., and the section is' taken with illustrators license in a manner to best serve` the purpose l ivithoiit departing from or modifying the invention, or inventions involved in thewhole structure.V

`In Fig. 1 the spokes al are shown-- tan entialtothe vcentralhu'b B, and indicate" 'as lthe blade by the sockets, as described, the v,rimA being secured about the middle line or axis' of' the propeller, while F-F are secured near the lateral edges of the-propeller l there being a lateral protuberance on the blade to afford a purchase or anchorage for the sockets F', at a lateral distance from the axis of the propeller as great as possible for purposes of strength. In Fig. l the shape of the propeller is shown without any such lateral projections, but in Fig. 3 a modification is shown in which the lateral projections b form the steps or brackets for more convenient attachment of' the wheels DV-D. As shown in Fig. 2, a sheathing J on one side of the propeller may be used to protect the surface, and may be duplicated on the other side for the purpose of preventing the indentation of the sockets, or other fastening members into the material of the propeller when under strain or setting up.

It will be seen the truss construction as indicated in Figs. 6 and 7, results in tying together the three circular braces, each one of which is radially tied to afford the greatest rigidity with the lightest weight owing to the character of construction. The threecornered structure afforded by these rims when tied together gives additional great strengthl for the weight, and the circular rims as shown, or in any form contemplated afford an exceedingly strong, circumferential structure, and also laterally strong structure at a point considerably removed from the hub center to support the propeller blades and transmit the strain through the skeleton wheels to the hub centers, without the necessity of a large mass 1 of material at the butt end of each blade.

If the skeleton hub structure is carried to a point radially where it will support the propeller at the center of reaction, it will be obvious that the strain on the propeller Will be substantially balanced on both sides .of the point of attachment of the skeleton wheel rim structure. Having the lateral skeleton wheels supported, each edge of the propeller wheel in turn prevents the twisting, or at least minimizes the distortion of the propeller in pitch. The wheel spokes while usually of round wire of great l strength, can be made flat or fish section E, are shown in this figure radial,

tudinal strength of' ribbon, thereby affordingy the minimum resistance of air passing through the hub, and `in this manner useful reaction canbe taken from the propeller almost from the very center to its tip, instead of housing the large amount of central surface involved in present day construction.

Any suitable means can be used to properly anchor the butt end of the propeller to the central hub, and this may involve a special metal fitting to give support and prevent splitting of the wood or other materialof the blade, while still producinga light, practical construction. This also affords the opportunity of making with equal facility individual blades built-up into propellers of two, three 4or more blades, withu out the difliculties of matching the hub centers in the present form, and making a very bulky central portion, and with the additional advantage of individual bladesl or the entire propeller with the loss of any one blade. Suitable joints may be made in the wheel rims, while the blade sockets maybe so constructed as to serve as the junction of the different sections of the wheel rims, for the purpose of assembly. The general assembly can then be readily made and the trueness of the propeller adjusted by proper tensioning or tice members or tangential or radial as will appear from this disclosure.

In place of the lattice or trussed connections between wheel rims, it will be seen that a flat band or a broad cylindrical rim might be used giving great strength in the direction parallel to the axis of the propeller, and this rim secured to give the necessary torque strength. When so made such cylindrical rim may have openings to 'fit the section of the propeller and suitable flashing or fittings would then attach the rim to the propeller sides without the severing of the grain of the propeller so as to maintain the maximum transverse or longithe material of the spokes;

blades.

Various modifications may be made in the structures as herein shown and described, and various details will be added in the practice of my invention beyond the diagrammatic or illustrative drawings filed herewith, all without departing from the spirit of my invention, but what I claim and desire to secure by Letters Patent is:

An aircraft propeller comprising a hub and driving connections, a circular supplementary hub of relatively large diameter and laced to said hub to resist circumferential strain, a second supplementary hub member laced to the hub and laced-to the first supplementary hub to resist circumferential strain, a plurality of blades anchored rigidly against circumferential movement being able to replace avoiding the loss of Y on the Central hub and means for rigid supname to tliis speoiiieation7 in the presence port in the supplement hub members at a of two subscribing Witnesses, this 28 day ot' radius less than the effective blade area and March, 1916.

having said effective blade area projected SAMUEL D. MOTT. 5 Clear of all supporting and circumferential Witnesses:

strain members. HERMANN F. CUNTZ,

In testimony whereof, I have signed my H. MUCHMORE. 

